In the past three decades, though the effect of municipal sewage (point source
pollution) on the water quality of streams and rivers has received much attention, very little
work was reported on the treated sewage in India. Temperature is one of the most
important physical factors of the environment, as it has a profound influence on the survival
and distribution of its biotic communities, particularly planktonic organisms in the
aquatic ecosystem. The hydrogen ion concentration (pH) is an important abiotic parameter
and effects the diversity and distribution of species in any aquatic ecosystem. It also
controls the distribution of flora and fauna. pH ranging between 6.7 and 8.4 is suitable,
while values below 5.0 or above 8.8 are detrimental to acquatic life (Morrison et al., 2001). Sewage with a pH of less than 4 is acidic and much less productive than the alkaline waters
and the aquatic organisms in such water are often diseased (Girija et al., 2007). While more acidic conditions are detrimental, alkaline conditions support productivity and
diversity in the receiving water bodies (Morrison et al., 2001). Undoubtedly, the most reliable
way to control pollution and improve water quality is to stabilize the ecosystem by
balancing the input and output of ions in waste water (Morrison et al., 2001). Electrical Conductivity (EC) denotes the capacity of a substance in a solution to conduct electric current. The
EC in waste water is measured by a conductivity meter. Solids in waste water may either
be in the form of dissolved (soluble solids) or suspended solids (suspended solids).
Sewage with high dissolved solids will have a laxative effect. Total Dissolved Solids
(TDS) sometimes called non filterable solids are the substances that would pass through a
0.45 micron filter but remain as a residue when the water evaporates. They include,
dissolved minerals, salts and humic acid. The major contributors of TDS are carbonate,
bicarbonate, chloride, sulphate, phosphate and nitrate salts (Eugene, 2000). Total Suspended
Solids (TSS) in sewage are organic and mineral particulate matter that do not pass through
a filter. They include, silt, clay, metal oxides sulfides, algae, bacteria and fungi. TSS is
the major contributor to turbidity, which limits the penetration of light for
photosynthesis and visibility in the water bodies.
The total waste water generated per annum from 200 Indian cities is about
2,800 million cubic meter, of which 65-70% is not treated (Kaul et al., 1989). CPCB (2005), reported that domestic sewage from cities and towns is the biggest source of pollution of
water bodies in India. Studies on the spatio-temporal variations of these parameters in
rivers and canals receiving municipal sewage and effluents have been carried out by
various earlier researchers in India River Kathajodi (Das and Acharya, 2003), Yamuna
(Ravindra et al., 2003) and Cooum (Jebanesan et al., 1992), and in other countriesOsun river
in Nigeria (Olajire and Imeokparia, 2001), and Marimba River in Zimbabwe (Nhapi
and Tirivarombo, 2004). Akpan (2004) reported average conductivity in Akpatak and Iba
Oku streams in Nigeria. Inggard and Dag (1997) reported on the pH variation in
Hoylandet stream in Norway. The present study attempts to report the seasonal effects of raw
and treated sewage on the water quality, Temperature, pH, Conductivity, TDS and TSS in
the Buckingham Canal at Kalpakkam on the east coast of Tamil Nadu. |
